<%@ page contentType="image/jpeg" import="javax.imageio.ImageIO,
java.awt.*,java.awt.image.BufferedImage,java.util.Random" %>
 <%! 
Color getRandColor(int fc,int bc) 
{ 
Random random = new Random(); 
if(fc>255) fc=255; 
if(bc>255) bc=255; 
int r=fc+random.nextInt(bc-fc); 
int g=fc+random.nextInt(bc-fc); 
int b=fc+random.nextInt(bc-fc); 
return new Color(r,g,b); 
} %> <%
out.clear(); //这句针对resin服务器，如果是tomacat可以不要这句
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
int width = 60, height = 20;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
Random random = new Random();
g.setColor(getRandColor(200, 250));
g.fillRect(0, 0, width, height);
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
g.setColor(getRandColor(160, 200));
for (int i = 0; i < 155; i++) {
    int x = random.nextInt(width);
    int y = random.nextInt(height);
    int xl = random.nextInt(12);
    int yl = random.nextInt(12);
    g.drawLine(x, y, x + xl, y + yl);
}
String sRand = "";
for (int i = 0; i < 4; i++) {
    String rand = String.valueOf(random.nextInt(10));
    sRand += rand;
    g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
    g.drawString(rand, 13 * i + 6, 16);
}
// 将认证码存入SESSION
session.setAttribute("random", sRand);
g.dispose();
ImageIO.write(image, "JPEG", response.getOutputStream());
%>

